1. Field of the Invention
The present invention relates to an image formation apparatus and an image formation system which can output a sheaf of sheets composed of a specific sheet such as a cover or the like and sheets on which images were respectively formed.
2. Related Background Art
Conventionally, there has been provided an image formation apparatus such as a copying machine or the like which has a mode such as a cover mode, a slipsheet mode or the like in which a sheet (referred as a specific sheet hereinafter) different from an ordinary recording sheet is inserted in a head page, a final page or an intermediate page of the recording sheets. If such the mode is set, for example, a sheet having different color or a color copy sheet can be inserted as a cover, or a divider for dividing or partitioning an arbitrary number of sheets. Further, in a copying machine connected with a sheet processing apparatus such as a finisher or the like, a sheaf of sheets in which the specific sheets and the recording sheets mixedly exist can be subjected to stapling processing or the like for book binding.
As a specific sheet feeding method, it has been known a method which feeds the specific sheet from a special cassette provided on the side of the body of the copying apparatus. In such the method, the specific sheet is fed from the special cassette at the timing when the specific sheet is to be inserted, and the fed specific sheet is discharged outside the copying machine through the carrying path identical with the carrying path used for the sheet on which an image was formed. Namely, the specific sheet is discharged outside the machine through an image formation unit in which a fixing unit and the like are disposed.
However, when the specific sheet is fed from the cassette disposed on the side of the body of the copying machine, if a sheet such as a color-printed original or the like is used as the specific sheet, the sheet passes the fixing unit. Thus, since the sheet is effected by thermal pressure at this time, there is some fear that image quality of the sheet deteriorates. Further, in recent years, the color copy sheet has been often used as the specific sheet. Thus, if the color copy sheet is fed from the cassette provided on the side of the body of the copying machine, there is some fear that oil or the like on the face of the color copy sheet deteriorates carrying capability of a sheet feeding mechanism and thus influences sheet carrying.
On the other hand, it has been proposed a method in which a sheet feeding unit for feeding the specific sheet such as the cover or the like is disposed on the side of the sheet processing apparatus such as the finisher or the like so, and thus the specific sheet is directly fed from this sheet feeding unit. Such the method is disclosed in Japanese Patent Application (Laid-Open) Nos. 60-180894, 60-191932, 60-204564, and the like.
Thus, it has been proposed that a stacking unit for the specific sheets is provided on the image formation apparatus or on the sheet processing apparatus such as the finisher or the like, and the specific sheet fed from the stacking unit and the sheets on which the images were respectively formed by the image formation unit are sheaved as one sheaf of sheets according as the specific sheets are set to the stacking unit by a user.
However, the user himself must set the specific sheet such as the cover or the like to the stacking unit. Therefore, if the user wishes to output the sheaf of the sheets which is composed of the specific sheet and the sheets on which the images were respectively formed by the image formation unit, he must set the specific sheet to the stacking unit after he sufficiently understands the internal structure of the apparatus. In other words, if the user does not understand how the image is formed on the sheet by the image formation unit, by what discharge method the sheet on which the image was formed is discharged from the image formation unit, how the sheet on the stacking unit is fed and discharged, and the like, there is some fear that inconvenience is caused in the output result which consists of the specific sheet and the sheets on which the images were respectively formed by the image formation unit. Concretely, there is some fear that page order becomes unconformable, or the directions of the images of the continuous pages become unconformable. In such a case, every time the inconvenience is caused, the user himself must confirm and correct such the inconvenience for each page. Further, in such a case, if the sheaf of the sheets was subjected to binding processing such as the stapling processing or the like, this sheaf of sheet is bound in the state that binding positions of the sheets are uneven, whereby the output result of this case is valueless. Thus, the user must again generates the identical data corresponding to the specific sheet used in such the output result and performs the above-described processing. Further, in the conventional proposal of the apparatus which can output the sheaf of the sheets composed of the specific sheet such as the cover or the like and the sheets on which the images were respectively formed by the image formation unit, it was not considered that the structure of the entire apparatus is prevented from enlarging, that the structure of the entire apparatus is prevented being complicated, and that productivity is improved.